I am currently running a new(ish) Problem Management process, it has been running for about 6 months now and it is beginning to mature, I have a dashboard and a regular review board meeting Etc. set up,

I also have broken the Problem Records down by priority and have a few lists based on different criteria to determine which are key and which are the "Nice to have fixed" list ...

The question is, what rules should I now apply around keeping to Problem Records updated?

I think for Priority 1&2 issues, where my main focus lies the answer would be weekly progress updates, but for the priority 3 & 4 records what sort of update frequency would be acceptable?

Obviously, it appears your P1s are not that urgent or impacting to the customer(s).

As to the question, how often.

The phrase - IT Depends must be the answer

If the team involved in the work do nothing on it for a week, yeah, update - no activity, but there should be some sort of update when there is an update_________________John Hardesty
ITSM Manager's Certificate (Red Badge)